JPH1119986A - Production of injection molded piece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method for an injection molding piece that is free from a dimension failure of a molded piece and which needs no painting process and causes no risk of a weld line being generated. SOLUTION: A production method for an injection molded piece comprising the steps of injecting a molten resin into a cavity formed when a female mold 2 and male mold 5 that are provided to confront each other are closed together, opening up the female mold 2 and the male mold 5 and removing a molded piece from the male mold 5, said method further comprising the steps of inserting an arm member between the female mold 2 and the male mold 5 when they are opened up, and removing a molded piece from the male mold 5 with a removing member 43 mounted on one side of the arm member while bringing a heating member 42 mounted on the other side of the arm member into contact with the mold surface of the female mold 2 to heat the same and.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an injection molded article.

[0002]

2. Description of the Related Art Conventionally, as described in Japanese Patent Publication No. 1-88864, molten resin is injected into a cavity formed when a female mold and a male mold provided opposite to each other are closed. In addition, there is known a method of manufacturing an injection molded product in which a female die and a male die are split and a molded product is taken out from the male die.

In such a method of manufacturing an injection-molded article, a so-called weld line may appear at the junction of the molten resin in the cavity, which may reduce the commercial value. As shown in FIG. 5, when the exterior part (a) of the office equipment is molded by the injection molding method, as shown in FIG. 6, a runner (b) provided at the center opening of the exterior part (a). In order to inject the molten resin into the cavity from above, weld lines (c) appear at the four corners of the exterior part (a).

Conventionally, in order to eliminate such a weld line (c), the number of gates for introducing a molten resin into the cavity is reduced, or the weld line (c) that appears on a molded product is painted over. I was

[0005]

However, as described above, when the number of gates for introducing the molten resin into the cavity in order to eliminate the weld line is reduced, dimensional defects of the molded product may occur. Coating from above the weld line appearing on the molded product has a problem that the cost is increased due to the necessity of a coating process.

The present invention has been made in view of such problems in the conventional method of manufacturing an injection-molded article, and an object of the present invention is to solve the above-mentioned problems and to improve the dimensional defect of the molded article. An object of the present invention is to provide a method for producing an injection-molded article which does not cause any wrinkling and does not require a coating step.

[0007]

In order to achieve the above-mentioned object, a method of manufacturing an injection-molded article according to the present invention is directed to a method of manufacturing a molded product in which a female mold and a male mold provided opposite to each other are formed when a female mold and a male mold are closed. In a method of manufacturing an injection-molded article by injecting a molten resin into a female mold and a male mold, and removing the molded article from the male mold, the arm member is split between the female mold and the male mold when the female mold and the male mold are split. The heating member attached to one side of the arm member is brought into contact with the female mold surface to heat the female mold surface, and the removal member attached to the other side of the arm member. It is characterized in that a molded article is taken out from the male mold.

In the method of manufacturing an injection-molded article of the present invention, the arm member is inserted between the female mold and the male mold when the female mold and the male mold are split, and attached to one side of the arm member. The heated member is brought into contact with the female mold surface to heat the female mold surface and to remove the molded article from the male mold by a removal member attached to the other side of the arm member.
By contacting the heating member, the female mold surface is heated so that no weld line appears, and the molded article can be taken out by the common arm member to which the heating member is attached, which is efficient.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view showing one embodiment of the method for producing an injection-molded article of the present invention.

In FIG. 1, 1 is an injection molding machine, 11 is an injection device of the injection molding machine 1, 12 is a mold moving device, 13 is a fixed die plate, and the female die 2 is mounted on the fixed die plate 13. Have been. Also, the fixed die plate 13
, A stand 3 is attached, and a robot 4 is attached to an upper end of the stand 3.

Reference numeral 14 denotes a moving die plate, on which the male die 5 is mounted. The female mold 2 and the male mold 5 are provided to face each other, and a cavity is formed between the female mold 2 and the male mold 5 when the female mold 2 and the male mold 5 are closed.

An arm member 41 is vertically provided on the robot 4, and the arm member 41 can reciprocate in the left-right direction and the depth direction in FIG. Arm member 4
A heating member 42 is attached to one side close to the female mold 2 of 1.
The heating member 42 includes two heating elements 422 and 42 on a base 421.
2 are installed.

The heating elements 422 and 422 are made of copper, aluminum, zinc, or the like, which is softer than the material of the female mold 2 and has excellent heat conductivity, and a cartridge heater is provided therein.
It is designed to be heated to a temperature of about 200 to 300 ° C. The surfaces of the heating elements 422 and 422 are coated with a heat-resistant rubber film so as to be in close contact with the mold surface of the female mold 2.

A take-out member 43 is attached to one side of the arm member 41 close to the male mold 5. Take-out member 43
Has a plurality of suction cups 432 attached to a base 431.

Next, one embodiment of the method for producing an injection-molded article of the present invention will be described with reference to FIGS. As shown in FIG. 1, in a state where the female mold 2 and the male mold 5 are split,
The arm member 41 is inserted between the female mold 2 and the male mold 5, the heating member 42 is moved in the direction of the female mold 2, and the plurality of heating elements 422 of the heating member 42 are brought into close contact with the mold surface of the female mold 2. Let the female mold 2
Is heated to a temperature of about 200 to 300 ° C.

Next, the arm member 41 is connected to the female mold 2 and the male mold 5.
, The female mold 2 and the male mold 5 are closed, the molten resin is injected into a cavity formed between the female mold 2 and the male mold 5, and a desired molded product is formed. With the molten resin cooled and solidified, the female mold 2 and the male mold 5 are split, and the female mold 2 and the male mold 5 are opened.
The arm member 41 is inserted between the male member 5 and the take-out member 43 is made to approach the male mold 5, and the suction cup 432 of the take-out member 43 is brought into close contact with the molded product attached to the male mold 5 to be sucked. By moving the molded product in the direction of the female mold 2, the molded product is released, and the heating elements 422, 4
22 and the mold surface of the female mold 2
After heating to a temperature of about 300 ° C., the same cycle is repeated thereafter to produce a molded product.

The heating elements 422 and 422 of the heating member 42 are brought into close contact with the mold surface of the female mold 2 so that the mold surface of the female mold 2 is 200 to 300.
By heating to a temperature of about ° C., a welded line does not appear in a molded product, and a beautifully molded product can be manufactured.

FIG. 3 shows an example in which another example of the heating member is used. In the heating member 42a shown in FIG.
Instead of using a plurality of heating elements 422 as in the heating member 42 shown in FIG. 2, one heating element 422a is used.

Although the embodiment of the present invention has been described with reference to the drawings, the configuration of the present invention is not limited to the illustrated embodiment, and design changes within the scope of the present invention may be made. Included in the present invention.

For example, instead of the arm member 41 moving left and right as in the embodiment shown in FIGS. 1 to 3, only the heating element 422b moves left and right like the heating element 422b shown in FIG. You may.

[0021]

According to the method for producing an injection-molded article of the present invention, since a female mold surface is heated by contact with a heating member and no weld line appears, a beautiful molded article can be produced. And the dimensional accuracy is also good. Further, the molded product can be taken out by the common arm member to which the heating member is attached, which is efficient.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a method for producing an injection-molded article of the present invention.

FIG. 2 is an enlarged partial cutaway front view of a main part of the embodiment shown in FIG. 1;

FIG. 3 is an enlarged partial cutaway front view of a main part showing another embodiment of the method for producing an injection-molded article of the present invention.

FIG. 4 is an enlarged front view of a main part showing still another embodiment of the method for producing an injection-molded article according to the present invention.

FIG. 5 is a perspective view showing an example of an injection molded product.

FIG. 6 is a front view showing a mode in which a weld line appears on an injection molded product.

[Explanation of symbols]

 Reference Signs List 1 injection molding machine 11 injection device 12 mold moving device 13 fixed die plate 14 moving die plate 2 female die 3 stand 4 robot 41 arm member 42 heating member 43 take-out member 5 male die

Claims (1)

[Claims] 1. A molten resin is injected into a cavity formed at the time of closing a female mold and a male mold provided opposite to each other, the female mold and the male mold are split, and a molded article is formed from the male mold. In the method of manufacturing an injection-molded product to be taken out, an arm member is inserted between the female mold and the male mold when the female mold and the male mold are split, and a heating member attached to one side of the arm member is attached to the female mold surface. And heating the mold surface of the female mold by removing the molded article from the male mold by a removal member attached to the other side of the arm member.